The present invention relates to a conveyance device that conveys a conveyed object in a predetermined conveying direction and an image forming apparatus.
Conventionally, there is a known conveyance device that conveys a carriage having a recording head (an ink-jet head or the like) mounted thereon in a main scanning direction. The conveyance device is included in an image forming apparatus that forms an image onto a sheet (paper or the like) placed below the recording head. In this kind of image forming apparatus, it is known that when a curled sheet or a bent sheet is fed, the recording head or the carriage may be brought into contact with the sheet and a paper jam may thereby occur.
In an image forming apparatus that includes an ink-jet head as a recording head, a nozzle part of the ink-jet head is poor in impact resistance, and when some force is applied to the nozzle part due to contact with a sheet, the nozzle part may be damaged. Therefore, measures are conventionally taken in which conveyance of the carriage is stopped by bringing a motor to an emergency stop. For example, a target position or a target speed, which is provided to a control system that controls the conveyance of the carriage, is compared with an actual position or an actual speed of the carriage measured by an encoder. If a difference between a target value and a measured value exceeds a threshold, it is determined that a load applied to the motor, which supplies drive power to the carriage, is abnormally increased due to a paper jam or the like. Based on the determination, the motor is brought to an emergency stop.